Lighting device

ABSTRACT

A lighting device comprises a discharge lamp ( 7 ) which is connected to a ballast and starting device ( 1 ) either directly or via an electric cable ( 4 ). Alternatively said discharge lamp ( 7 ) can be mechanically and electrically coupled to an external starting device ( 5 ) and electrically connected to the ballast and starting device ( 1 ) via a connecting cable ( 4 ).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of International application numberPCT/DE99/03074, filed Sep. 20, 1999, which in turn claims priority toGerman patent application number 198 44 293.9, filed Sep. 18, 1998.

BACKGROUND

The invention relates to a lighting device.

By contrast with incandescent lamps, discharge lamps have the advantageof a substantially higher light yield and/or economic efficiency. Theoperation of discharge lamps requires a ballast and a starting device,of which the starting device provides the starting voltage required forstarting the gas discharge, whereas the ballast limits the lamp currentof the discharge lamp during its operation after it has been started.

The starting voltage must overcome the resistance in the discharge lamp,and is proportional to the prevailing gas pressure. It can be up to 50kV, but must be present only briefly as a high-voltage pulse.

After the discharge lamp has been started, resistance decreases insidethe discharge lamp, and the lamp current, previously very low, can riseto impermissibly high values owing to the negative resistancecharacteristic of the ionized gas. A ballast with a positivecurrent-voltage characteristic is therefore necessary to limit thecurrent. Ballasts can be constructed as inductor ballasts or aselectronic ballasts, it being impossible to achieve a robust design, ahigh operational reliability and ease of use with inductor ballasts.However, they require a relatively large lamp installation space, cannotcompensate the lamp tolerances and changes in system voltage, and arerelatively heavy.

Electronic ballasts compensate fluctuations in system voltage and infrequency over a certain range, but are less robust and likewise requireinstallation space and appropriate cooling devices, and entailadditional weight.

The operation of a discharge lamp by means of a ballast and startingdevice is general prior art, and is described in DE 43 01 184 C2, forexample.

Normally, ballast and starting device are accommodated in the housing ofthe lighting device, that is to say in the vicinity of the dischargelamp, since in the case of a large length of lead from the ballast andstarting device to the discharge lamp excessively large losses occurand/or an excessively large voltage drop occurs, and so reliableoperation of the discharge lamp is not ensured. However, the lightingdevice becomes very large and cumbersome when the ballast and startingdevice are connected to the discharge lamp.

A further disadvantage of the known lighting devices consists in that adedicated ballast and/or starting device is required for each dischargelamp, and this leads to substantial costs when a plurality of dischargelamps are used.

U.S. Pat. No. 5,691,603 discloses the connection of a plurality oflighting units to a central power supply, with a rectifier connected toa voltage source and having a downstream smoothing circuit to which aninverter bridge circuit is connected as a starting circuit for aplurality of lighting units. A socket of the central power supply isconnected via fuses to an output transformer of the inverter bridgecircuit and can be connected to a plug which produces an electricconnection to the socket of a first lighting unit via a connecting line.This first lighting unit includes a ballast transformer and a seriesinductor and a fluorescent lamp.

Also provided is a through line which connects the socket-contact of thefirst lighting unit via an output socket-contact fitted on the firstlighting unit to a further lighting unit which likewise includes aballast transformer, a series inductor and a fluorescent lamp.

This document does not indicate how a compact structural unit can becreated between the discharge lamp and an external starting device, onthe one hand, and the discharge lamp and a ballast and basic startingdevice, on the other hand.

DE 33 23 930 A1 discloses a ballast and starting device for a gasdischarge lamp fed from an AC circuit, which combines power-independentswitching elements, specifically a rectifier bridge circuit, acurrent-limiting capacitor, a rectifier multiplier circuit and abipolar, electromagnetic current impulse changeover switch in a startingsection housing, and power-dependent switching elements, specificallyseries-connected capacitors with parallel-connected smoothing capacitorsand a discharge resistor in a nominal power section housing can beinterconnected electrically and mechanically via plug-in contacts, itbeing possible to connect the discharge lamp with an upstream smoothinginductor to DC voltage outputs of the starting section housing.

SUMMARY

It is the object of the present invention to create a lighting devicewhich can be used in a versatile fashion and even in the case ofrestricted available space, is of low weight and overall volume ifrequired, ensures a compact, closed design, can be producedcost-effectively, and ensures stable operation which is insusceptible tointerference.

The operation of the lighting device in various arrangements of adischarge lamp with a ballast and starting device widens the field ofuse of such lighting devices and also their ease of use, and permitscost-effective production and cost-effective operation of the lightingdevices.

Since the discharge lamps are connected mechanically and electrically ina detachable fashion to the ballast and operating device, it is possiblefor different, and also a plurality of, discharge lamps to be operatedsimultaneously with one ballast and starting device.

A discharge lamp with small dimensions which can also be used atlocations which are difficult to access is created by the mechanical andelectrical coupling of the discharge lamp to an external startingdevice, which is connected via a connecting cable to thecurrent-limiting circuit of a ballast and basic starting device inconjunction with bridging of the starting circuit of this device.

Since the discharge lamp is operated spatially separately from theballast and basic starting device, the discharge lamp can be startedindependently of the relatively large and heavy ballast and thus has alow weight and can, in particular, advantageously be used in constrictedspace conditions. The transmission losses and voltage losses areminimized by the short spacing and the short line paths, associatedtherewith, between the discharge lamp and external starting device, thusensuring reliable operation of the discharge lamp.

It is recommended in this case that when the discharge lamp is operatedwith an external starting device the adapter is used to produce a directconnection, avoiding the basic starting device, to the ballast bybridging the current-limiting circuit of the basic starting device. Thiscan be done, for example, by an appropriate electric or electroniccircuit arrangement, a switch or via a connect assignment of theadapter. In addition to low electric losses and to produce a closedstructural unit between the external starting device and the dischargelamp, the external starting device can be fastened directly withoutfurther adapters on the discharge lamp, or on the housing of thedischarge lamp.

In an advantageous development of the invention, the connection betweenthe discharge lamp and housing of the ballast and basic starting deviceis implemented via an adapter, by means of which an interface isproduced between the ballast and basic starting device and dischargelamp which is fixed and can be applied for a plurality of units. Theadapter can be a separate component or integrated into one of themodules to be connected.

In one variant of the invention, a plurality of adapter connections areprovided on the starting device so that a plurality of discharge lampscan be started with the aid of one starting device. Particularly in thecase of electronic ballasts, it is possible for the lamp current of aplurality of discharge lamps to be controlled with the aid of a singleballast.

For reasons of easy assembly and of quick lamp changing, given that itis also possible to operate different discharge lamps on one externalstarting device, it is expedient for the external starting device tohave an adapter connection of the ballast and basic starting device. Itis possible in this way to operate the discharge lamp via an adapterconnection both on the ballast and basic starting device and on theexternal starting device, without the need for structural changes oradapters.

It is favorable to be able to connect the connecting cable to theballast at various points of the external starting device in theinterest of the most variable use possible of the discharge lamp in theuncoupled mode. For this reason, the connecting cable has a plug whichcan be connected to a plurality of sockets of the external startingdevice.

An advantageous refinement of the solution according to the invention ischaracterized in that the sockets of the external starting device havedifferent alignments or orientations. For example, one orientation isprovided in the direction in which the lamp emits light, and one isprovided at right angles to the direction in which the lamp emits light,in order to have as large a number as possible of options forcombinations and arrangements in conjunction with the possible forms ofplug, for example straight or right-angle plugs. Of course, otherorientations relative to the direction of light emission or a maindirection of expansion of the lamp housing are possible.

In accordance as well, it is advantageous for reasons of variabilitythat the sockets and the adapter connections are compatible, so that,for example, a plurality of discharge lamps can be connected to aballast by means of the external starting devices in differentdirections of light emission.

In one embodiment of the invention, the adapter connection or thesockets is constructed as a bayonet lock, the bayonet lockadvantageously having a rotatable contact plate, in order not to damagethe mechanical locking of the electric contacts.

The idea on which the invention is based is to be explained in moredetail with the aid of exemplary embodiments illustrated in the drawing,in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagrammatic illustration of a discharge lamp with acoupled-on ballast and basic starting device;

FIG. 2 shows a diagrammatic illustration of a discharge lamp having acoupled-on external starting device;

FIG. 3 shows a diagrammatic illustration of the operation of a pluralityof discharge lamps each connected to one external starting device, on aballast and basic starting device;

FIGS. 4A-C show a front view and side views of a discharge lampconnected mechanically and electrically to a ballast and basic startingdevice;

FIGS. 5A-B show a front view and a side view of a discharge lampconnected mechanically and electronically to an external startingdevice, and electrically to a ballast and basic starting device;

FIGS. 6A-C show a front view, a rear view and a section through acontact plate of an adapter or adapter connection, and

FIGS. 7A-C show a front view, a rear view and a section through asupport plate of an adapter or adapter connection.

DETAILED DESCRIPTION

FIG. 1 shows a diagrammatic illustration of a lighting device B having aballast and basic starting device 1, on which a discharge lamp 7 isfastened. Although electrically the ballast and the basic startingdevice form two separate components, these are denoted jointly asballast and basic starting device 1. If reference is made to one of thetwo components separately, these are denoted as ballast 1 a and basicstarting device 1 b.

Arranged on the ballast and basic starting device 1 is an adapter oradapter connection 2 which is expediently integrated into the housingbut, for reasons of clarity, has not been illustrated separately here.

The discharge lamp 7 together with the lamp housing is fastened via theadapter connection 2 in such a way as to produce the structural unitwith the ballast and basic starting device 1. In this way, the lightingdevice B differs from conventional luminaires in having a modular designby means of which various discharge lamps 7 can be operated on astandard ballast and basic starting unit 1. The adapter or adapterconnection 2 is constructed in this case in such a way that thedischarge lamp 7 is permanently connected mechanically to the ballastand basic starting unit 1, such that it is possible to arrange thelighting device B on a stand or the like. The electric connection of thedischarge lamp 7 to the ballast and basic starting device 1 is likewiseperformed via the adapter or adapter connection 2 by means of electricjacks or contact connectors which are integrated therein and makecontact with corresponding mating sockets or mating connectors on thedischarge lamp 7 or on the ballast and basic starting device 1 when thedischarge lamp 7 and ballast and basic starting device 1 are connectedmechanically.

FIG. 2 shows a variant of the lighting device B, in the case of whichthere is connected at the adapter connection 2 of the ballast andstarting device 1 an adapter 3 which is connected to an externalstarting device 5 via a connecting cable 4. The external starting device5 has, for its part, an adapter or adapter connection 6 which can becoupled mechanically to an adapter of the discharge lamp 7 and via whichthe discharge lamp 7 can be connected electrically to the externalstarting device 5.

Since a starting device can be designed to be relatively small andlight, the mobility or the field of use of the discharge lamp 7 is onlyinsubstantially limited by a combination of the external starting device5 with the discharge lamp 7. The direction in which the discharge lamp 7emits light is indicated in FIG. 2 by the arrow, and this signifies thatthe external starting device 5 is connected at the rear side of thedischarge lamp 7. A very narrow design can be achieved by thisarrangement. However, it is also possible to place the external startingdevice 5 to the side of the discharge lamp 7 or on the lamp housing.

During operation it is expedient to use an external starting device 5 toproduce a direct connection to the current-limiting circuit of theballast 1 a of the ballast and basic starting device 1, since thestarting circuit of the basic starting device 1 b is not required.Alternatively, it is also possible to bridge only the capacitor of thebasic starting device 1 b.

Since, in accordance with a further feature of the invention, theadapter or adapter connection at the discharge lamp 7 can also bedirectly coupled to an adapter or adapter connection of the connectingcable 4, it is also possible to produce a direct connection of thedischarge lamp 7 to the adapter 3 of the ballast and basic startingdevice 1 without bridging the starting circuit of the ballast and basicstarting device 1.

FIG. 3 shows the arrangement of a plurality of discharge lamps 7, 7′,connected to external starting devices 5, 5′, via cables 4, 4′ andadapters 3, 3′ and also adapter connections 2, 2′ at a ballast andstarting device 1. The design corresponds in principle to the designillustrated in FIG. 2, there being arranged here at the externalstarting devices 5, 5′ two sockets 8, 8′ to which one connecting cable4, 4′ each can be connected. These sockets 8, 8′ can be arranged atdifferent angular positions to the direction of light emission or to thelamp housing and/or to the external starting devices 5, 5′.

All forms of sockets are suitable in principle; for reasons of themodular design, it is to be recommended, however, to construct thesockets 8 in a fashion compatible with the adapter connections 2, sincethis creates a multiplicity of possible arrangements.

FIGS. 4A-C show a front view and side views of a discharge lamp 7directly coupled mechanically and electrically to a ballast and basicstarting device 1. The coupling is performed via an adapter withmechanical and electrical connecting elements on the ballast and basicstarting device 1 and on the discharge lamp 7. In this exemplaryembodiment, the ballast and basic starting device 1 has an articulationfor connecting to a stand or to a suspension of the lighting device.

FIGS. 5A-B show a front view and a side view of a discharge lamp 7connected mechanically and electrically to an external starting device5, and a ballast and basic starting device 1 which is connectedelectrically to the external starting device 5 via a connecting cable 4.The length of the connecting cable 4 is 3.5 or 7 meters in a preferredembodiment.

Whereas in FIGS. 4A-C, for example, the total length of the lightingdevice formed from the ballast and basic starting device 1 and dischargelamp 7 is approximately 200 mm, the lighting device assembled in FIG. 5from the discharge lamp 7 and external starting device 5 has a length ofonly approximately 96 mm.

The connection of the individual components of the lighting device(ballast and basic starting device 1, connecting cable 4, externalstarting device 5 and discharge lamp 7) can be performed via differenttypes of sockets and adapters or adapter connections, depending onwhether a purely electrical or electrical and mechanical connection isprovided according to this subject matter of the invention. One designof the sockets 8 or adapter connections 2, 6 is the bayonet lock, inparticular with a rotable contact plate, since this creates a reliableand quick mechanical and electrical connection without endangering theelectric contacts.

FIGS. 6A-C and 7A-C illustrate various views of adapter connections 2, 6which are constructed as bayonet locks and serve for the purpose ofconnecting the discharge lamp 7 to the external starting device 5, theballast and basic starting device 1 or the connecting cable 4, and/or ofconnecting the connecting cable 4 to the external starting device 5 orthe ballast and basic starting device 1.

In addition to the electric contacts 9, receptacles 10 for mechanicallocking are provided on the adapter connection 2, 6. The mechanicallocking is performed in this case in a known way by inserting fasteningpins (not illustrated) into the receptacles 10, followed by rotationthrough a specific angle.

The respective electric contacts 9 are closed at the same time as thefastening pins are inserted into the receptacles 10. In order to avoiddamaging the contacts during rotation, the contact or support plate 11is rotably designed as a rotatable contact or support plate 11.

List of Reference Symbols

1 —Ballast and starting device

1 a—Ballast

1 b—Basic starting device

2—Adapter connection

3—Adapter

4—Connecting cable

5—External starting device

6—Adapter connection

7—Discharge lamp

8—Socket

9—Electric contact

10—Receptacles

11—Rotatable contact or support plate

B—Lighting device

What is claimed is:
 1. A modular lighting device for theatre, film andstudio lighting devices, the lighting device comprising: a dischargelamp arranged in a lamp housing having a rear side with one of anadapter and an adapter connection, a ballast and basic starting devicehaving a current-limiting circuit and a housing with one of an adapterand an adapter connection, an external starting device having a startingcircuit and arranged in a housing with one of an adapter and an adapterconnection, a connecting cable connecting the external starting deviceto the ballast and basic starting device, and wherein one of the adapterand the adapter connection of the lamp housing mechanically couples toone of the adapter and the adapter connection of the ballast and basicstarting device and mechanically couples to one of the adapter and theadapter connection of the external starting device, such that astructural unit is produced, and wherein, upon coupling of the lamphousing to the housing of the external starting device, an electricconnection of the discharge lamp to the starting circuit of the externalstarting device and to the current-limiting circuit of the ballast andbasic starting device via the connecting cable is produced.
 2. Thelighting device according to claim 1, wherein the connecting cable isconnected to one of the adapter and the adapter connection of theballast and basic starting device via an adapter.
 3. The lighting deviceaccording to claims 1 or 2, wherein the connecting cable has one of anadapter and an adapter connection and the discharge lamp is connected tothe current-limiting circuit of the ballast and basic starting devicevia the adapter or adapter connection on the lamp housing and an adapteror adapter connection on the connecting cable.
 4. The lighting deviceaccording to claim 1, wherein the ballast and basic starting devicecomprises a plurality of adapter connections for various dischargelamps.
 5. The lighting device according to claim 1,wherein, duringoperation of the discharge lamp, the starting circuit of the ballast andbasic starting device is bridged by the external starting device, andthe current-limiting circuit of the ballast and basic starting device isconnected to the discharge lamp via the external starting device.
 6. Thelighting device according to claim 1, wherein the adapter connections ofthe ballast and basic starting device housing and of the externalstarting device are compatible.
 7. The lighting device according toclaim 1, wherein the external starting device has at least two socketsfor connecting to the connecting cable.
 8. The lighting device accordingto claim 7, wherein the external starting device comprises a lateralsurface and a rear surface; and the sockets are variously aligned andarranged on the lateral surface and on the rear surface, away from thedischarge lamp, of the external starting device connected to thedischarge lamp.
 9. The lighting device according to claim 7 or 8,wherein the sockets and the adapter and the adapter connection of theballast and basic starting device are compatible.
 10. The lightingdevice according to claim 7, wherein the adapter connections have arotatable contact plate and receptacles for mechanical connection tofastening pins of a mating adapter.
 11. The lighting device according toclaim 10, wherein the receptacles for mechanical connection to fasteningpins are constructed as a bayonet lock.
 12. A modular lighting devicefor theatre, film and studio lighting devices, the lighting devicecomprising: a discharge lamp arranged in a lamp housing having a rearside with one of an adapter and an adapter connection, a ballast andbasic starting device having a housing with one of an adapter and anadapter connection, an external starting device arranged in a housingwith one of an adapter and an adapter connection, a connecting cableconnecting the external starting device to the ballast and basicstarting device, and wherein one of the adapter and the adapterconnection of the lamp housing mechanically couples to one of theadapter and the adapter connection of the ballast and basic startingdevice, such that a structural unit is produced, and wherein, uponcoupling of the lamp housing to the housing of the ballast and basicstarting device, an electric connection of the discharge lamp to theballast and basic starting device is produced.
 13. The lighting deviceaccording to claim 12 wherein the connecting cable is connected to oneof the adapter and the adapter connection of the ballast and basicstarting device via an adapter.
 14. The lighting device according toclaims 13 wherein the ballast and basic starting device has acurrent-limiting circuit and the connecting cable has one of an adapterand adapter connection and the discharge lamp is connected to thecurrent-limiting circuit of the ballast and basic starting device viathe adapter or adapter connection on the lamp housing and the adapter oradapter connection on the connecting cable.
 15. The lighting deviceaccording to claim 12 wherein the ballast and basic starting devicecomprises a plurality of adapter connections for various dischargelamps.